This invention relates to a dial type wire control device in which a dial member rotates to drive a subject driven member by means of a wire.
FIG. 1 shows a conventional dial type wire control device. A dial member 1 is fixed to one end of a shaft 2. The other end of the shaft 2 is fixed to a pinion gear 3, like a bevel gear. The pinion gear 3 engages a fan shaped rack gear 4 which can rotate around a point 4a within a given range. A wire 5 is connected at one end to one end of the rack 4 and at its other end to a subject driven member (not shown). In operation, the roatation of the dial member 1 urges the rack 4 to rotate around the point 4a, whereby the wire 5 is pulled or pushed to actuate the subject driven member.
In such a conventional dial type wire control device, however, as the rotation of the dial member is transmitted to the rotation of the rack, a large space is necessary for rotation of the rack. Thus, such a conventional device can not be provided within a limited space. Also, because the input angle of the dial member 1 has a rectilinear relation with the output stroke of the wire 5, for example, when such a conventional device is applied to a blown-air temperature control system for a heater, the actual temperature of the blown-air does not change in strict correspondence with the input angle of the dial member, that is, the output stroke of the wire. Thus, a precise temperature control can not be obtained.